Process of sifting granular material



(NoModel.) 9 Sheets-Sheet 1.

' F. G. WINKLER.

`PROCESS 0F SIFTING GRANULAR MATERIALS.

(No Model.) 9 Sheets-Sheet 2.

- P. G. WINKLER.

PROCESS 0F SIFETINS GRANULAR SMTBRIALS.l No. 593,630. Patented Nov.16,1897.

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(No Model.) 9 Sheets-Sheet 3.

F. G. WINKLER.

PROCESS 0F SIFTING GRANULAR MATERIALS. No. 593,630. Patented Nov. 16,1897.

we Nonms PETERS co, PHo'roALrmo.. WASHINGTON, o. c.

9 Sheets-Sheet 4.

(No Model.)

P. G. WINKLER. PROCESS 0F SIPTING GRANULAR MATERIALS. No. 593,630.

Patented Nov. 16,1897.

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(No Model.)

. 9 Sheets-Sheet 5. F. G. WINKLER. PROCESS 0F SIFTING GRANULARMATERIALS.

No. 593,630. Patented Nov. 16,1897.

/m/J J JJ y 5. mwl/wwwedm www (No Model.) 9 Sheets-Sheet 6.

F. G. WINKLER.

PROCESS 0F SIPTING. GRANULAR MATERIALS. I No, 593,630. Patented Nov.16,1897.

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F. G. WINKLER.

I. PROCESS 0F SIFTING GRANULAR MATERIALS. No. 593,630. Patented Nov.1'6, 1897.

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' F. G. WINKLER.

PROCESS 0F SIFTING GRANULAR MATERIALS.

No. 598,630. l Patented Nov. 16, 1897.

(No Model.) v -9 Sheets-Sheet 9.

. I'. G. WINKLER.

PROCESS 0F SIPTING GRANULAR MATERIALS.

No. 593,630. Patented Nov. 16, 1897.

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NITE` STATES I Enron..

PATENT A PROCESS OF SIFTING GRANULAR MATERIAL.

SPECIFICATION forming part of Letters Patent No. 593,630, dated November16, 1897. Application filed August 14:, 1896. Renewed April 15, 1897.Serial No. 632,345. [No specimens.)

To all whom it may concern: Be. it known that I, FRrEDRIcH GEORG.WINKLER, a subject of. the Emperor of. Ger' `many, and a resident ofAJersey City, Hudson county, State of New Jersey, have invented: certainnewv and useful Improvements in Processes of Sifting GranularMaterials,ofl which the following is a specification.

This invention relates to a'proc'essof sifting granular material-such asiiour, meal, and other granular materials-through a sieve; and theprocess essentially consists in subjecting the said granular materialsto the action of air-currents inthe following manner: First, thematerials within the sieve are subjected: to the action of a long andstrong inward aircu'rrent, the volume and distribution of which areaccurately controlled and which frees the particles which are adheringto the inside of the sieve therefrom, and also brings large volumes ofair into the sieve. Then immediately the materials are subjected to theaction of a strong, sharp, and sudden outward current of air, whichsifts the finer particles through the sieve. This outwardsifting-current is then followed by a long and strong outwardafter-current, which blows the sifted particles far from the sieve, sothat such partieles cannot be brought back by the next inward current.

I have'found that the effective sifting of iiour, meal, and othergranularl substances through a sieve or homing-cloth requires that alarge volume, of air (much larger, in fact, than that heretoforeobtained) shall nbe made to pass both in and out of the sieve'orbolting-cloth, the volumepassing in and that passing out being of courseequal, for in order to insure high sifting efficiencies sufficient airmust be brought in to provide enough for a Very strong, swift, andsudden sifting impulse and also for a strong and long outwardafter-current, and if a large quantity of air is not brought in asufficient supply for such an outward after-current cannot beobtainedwithout taking away some of thev air that is needed for the strongsifting impulse.

. The air-wave must also be of such character th'e 'velocities of thefan.

succeeded at all they have proceeded upon sequent Aoutward currents, andalso to clear the inside of the sieve of all particles of the material,and'thereby prepare it for the sucoeeding sifting impulse; second, thisinward current must be immediately followed by a strong, swift, andsudden outward sifting-cur` rent, which propels thene particles of thematerial through the sieve; third, this sifting-current must beimmediately followed by -or continued into a prolonged and strongoutward after-current t0 project the iueparticles which passed throughVthe sieve` so far away that they cannot be caught by the next inwardcurrent. This outward after-current is indispensable, for if the firstoutward current be immediately followed by the next inward current moreor less of the fine material whichhad passed through the sieve' will becarried back through, into, and upon the sieve, greatly reducing theoutput and'impairing the efciency of the apparatus.

' Itis desirable th at the air-waves which generate theafore'saidcurrents through the sieve shall Abe producedat comparatively lowvelo'cities of the fan or pulsator, for high velocities-such, forexample, as twelve hundred or fteen hundred revolutions perminute-involve an excessive power cost and wear and tear.

The attempts heretofore made to produce a commercial sifting apparatushave been unsuccessful, particularly in respect of the volumeof airpassed through the sieve and in respect ofthe character of the air-wavesand So far as they have the principle of generating an air-wave that Wasintended to subject the material successively to the influencealternately of a relatively strong current of air moving outward througha small area of the sieve and a relatively weak current moving inwardthrough a larger area of the sieve and following immediately upon theoutward current; but in practice neither the relatively weak and longinward'curreut nor the relatively short and strong outward current wasever obtained, because an air-cushion was produced between thedeflecting-grate and the sieve before the.

real sifting impulse began, which materially impaired the siftingeffect. The result also of following up thesifting-current by the inwardcurrent, without an intermediate outward after-'current of 'considerableforce and volume, was that a considerable part of the ne material thathad just been sifted through the sieve was carried back through, into,and upon the sieve, the output greatly reduced, and the action ofthe/apparatus rendered very uncertain at moderate speed. This hascompelled the employment of Very high velocities, with consequent greatpower cost and wear and tear, and even then the action has beenuncertain, and to obtain a large siftingvv effect it has been necessaryto employ comparatively long sieves and-correspondingly" long pulsatorsand other parts. This has also greatly increased the power necessary todrive the machine, as well as the size :an'd'wei'ght of the machine.Such apparatus 'was :also constructed with cells open onlytoward theperiphery of the fan but'closedv inwardly and laterally. Theconsequence-was 'the crowding of the incoming air rand 4genera-tionofreturn currents which'shortened and then destroyed 'the inward currentsoon afterfi-t vwas .generated by creating a :gentle outward curyren'tof the air which formed the :aforesaid 'air-cushion between thedeiiecting-.grate :and

sieve long before the intended short 'and -strong outwardsifting-current 4began to :act and lessened greatly the volume of fairfand tlrelefiiciency of the machine. These defects forced a resort Itovery highvelocities inthe attempt to develop p'roperinward volume anddistribution of the currents; but-theattempt was unsuccessful, becausethefdistribution of the air inside of 'the -sieve was ywrong'inprinciple and could not be'control'led. lheprocess, however, which @istlresubject of -thefpresenit :application succeeds for `the first iti mein the art Yin the vperfect control both of the' incoming'and theoutgoing ai'r -currents #and also in bringing very large volumes of airint-o the machine, Aand -I havebeen enabled-toreduce the power cost bothby a materialredu'ction invelocities of revolution/andiabove all by thevgreat 'reduction of -the I'length of "the sieve,` fan, "and other parts'of 5the preferred form of y machine by which theprocessvis 'operated.These two facts combined have'refv resulted insolgreat aredu-ction'ofthepowen cost and wear and tear that myzpresent invention attains -anVeconomy of operation siftingfeect.

panying drawings, and which consists, essentially, of a sieve and outerdefieeting-grate in proximity to the sieve and a plurality of pressureland vacuum -generators independent of each other within the said outerdelectinggrate arranged concentrically to each other,

r so that the vacuums are developed in any succession determined uponand are regulated to maintain the inward ycurrent practically up to theinstant when the sudden sifting impulse begi-ns to operate. Theefficiency of this apparatus for operating lthe process depends upon thefacts, iirst, that the machine isy so formed that there are open spacesin the interior which-are connected together laterfally in such lmannerthat the `total inward current or volume of vair has `suiiicient roomwithout :generating return currents, which would :greatly reduce thevolume of air and impair @the effectof the inward current. Sec--ond,\that'the wave-'generator contains or is 'combined with a Vplu rality of vacuum-making ydevices .arranged concentrically within and'successively behind Aeach other, so'that the inner vacuum-makingdevices successively -act uponand increase or maintain Ithe'inwardcurrent previouslygenerated almost up .'currentwhi'ch is developed andcontrolled by :the-'successive vacuums rebounds or deiiects outward withimmense velocity'and powerful The intensity and force of this reboundarer,greatly increased by the aforesaid movement of the inner gratings in adirection opposte'to the movement'of the inner pressure-fans,'for theeffect of these opposite nrotionsis'that the incoming airis defiectediandfimpelled in a direction opposite to `that oft'h'efanblades lwhichgenerate the sifting impulse, andthe air'encounters no Aresistanceuntilitisaetually upon the said fan-blade. The'consequence is 'anextremely powerful 'outward-sifting impulse or current following almostvimmediately upon the stoppage of the inwardfcurrent. Third, thatthesifting-impulse :generator is succeeded by blades or :groups offanslwhich generate a prolonged fand -strong=outward after-current whichprojects'thelsifted materialfar from the sieve.

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ling as does the machine shown in Fig. 1.

Fourth, that the wave-generator is so opened on the interior that thedevices for said out, ward after-current get their air from the inwardcurrent, thereby preventing the crowding of the incoming air and aidingto maintain the inward currents. Fifth, that the air which passes fromthe inward currentsto the outward after-currents,as aforesaid, sweepsunder and keeps the inner surfaces of the 4blades or fans thoroughlyclean and prevents the accumulation of fine dust in the interior ofthewave-generator.

Referring to the drawings which accompany the specification to aid inexplaining how the process is operated, Figure 1 is a longitudinalvertical section of vthe preferred form of machine. Fig. 2 is averticalcrosssection on a larger scale and on the line 2 2 of Fig. 1. Fig-3 isaverticalcross-section, partly broken, on the line 3 3 of Fig. 1 and onthe scale of Fig. 2. Fig. 4 is an elevation of the left end of Fig. 1.Fig. 4a is a detail of the preferred device for driving the pulsator.`Fig. 5 is a vertical section, on a large scale, showing the preferredshape and relative positions of the gratings, suction-blocks, and fans.This figure illustrates parts of the same machine that is showninFig. 1. Figs. 7, 8,'and 9 are cross-sectional viewsA illustratingmodifications in the arrangement of gratings, suction-blocks, and fans,but all arranged to operate the same process of sift- Referring toFigs. 1. to 5, inclusive, A is the bolting-chest, within which-arearrangedy the sieve B, the concentricv gratings C C C2 C3, thevacuum-generators or suction-blocks d cl didi and the fans E E E2. Saidsieve B may either revolve or be stationary. The said gratingspreferably revolve in the direction of the arrow -1 Fig. 5--7. c., inthe direction opposite to the revolution of the sieve B, if said sieverevolves-and the said suction-blocks and fans (which, taken together, Iterm the pulsators, since they produce the pulsations of the air whichYare instrumental in developing the currents and distribution of thevolumes of airthrough the machine whereby the working of the process iseffected) preferably revolve at'comparatively high ,velocities in thedirection opposite to the revolution of the deflecting-grates. Saidsieve B is a cylindrical vreel having its peripheral wall formed of asuitable screen Vor bolting-cloth stretched in any known and usualmanner on frames 1 2, Fig. 2. At one end the said frames are. fastenedto rims 4, Fig. 1, carried on the ends of radial arms 5 5 of a. circularhead 6,` Fig. 3, and the other end of said frame lis fastened to acircular head 7, which is bent and flanged at its outer part, as shownin Fig. 1. Openings 8 S between said arms 5 5 permit the tailings'topass out` to the discharge-chute WV. A iianged rim 9 on said head 6revolves with dust-tight fit in a circular groove 10, formedvin theframe in the usual manner, and said head 6 carries a carry thesuction-blocks and fans.

lof the outer circle of deiiecting-grates C, howhollow hub 1.1, whichturns in boxes 12, carried by the frame. The hollow hub 15 of the head7, and which is of sufficient diameter to serve as the inlet for thematerial to be septoo coarse for the mesh of the basket will be retainedthereby; Removable plugs 18 19 are provided to give access to saidbasket.

The aforesaid gratings are preferably arranged in concentric circles C CC2 C3, as shown in Fig. 5. The gra-tes or bars of each circle arearranged in two parts or halves, one part being fastened to vthe head 2Oand the other partto the head 21, and, if desired, the number and shapeof the bars in the one part may differ from those in the other part. Thebars of the outer circle C are each preferably'bent, as shown incross-section, Fig. 5, to give the air-currents a directionapproximately radially outward, and the bars of the inner circles ofgratings C' G2 C3 may be either curved, bent, or fiat. circles C C2 C3extend from their respective heads 20 or 21 nearly to the middle ofthemachine; but sufficient space is leftbetween the inner ends of saidbars to permit of the free revolution ofV the wings 2525, Fig. 2, whichever, extend entirely across from the head 2O to the head 21, and saidbars are preferably held in Vframes secured on said heads, as in dicatedin Fig. 1.

In the machine illustrated in the drawings all the gratings are ofcourse driven from the same shaft or hub; but each circle of gratingsmay, ifdesired, be constructed so as to be driven independently of allthe others. Referring to-Fig. 1, the hollow hub 27 on head 20 passesthrough hollow hub "11 and turns in boxes 29, and the hollow hub 30of'head 21 passes through hollow hub 15, there being a good spacebetween saidhubs 30 and 15, and turns in boxes 32. A spiral conveyer 34on hub V30 works the materials toward and into the aforesaid basket G.

The aforesaid suction-generators D D D2D3 are preferably formed asblocks d CZ (Z2 d3, which I term suction-blocksand .which are preferablycurved on their rear or. suction side, as shown in Fig. 5. Saidsuction-blocks d d d2 d3 are arranged and fastened inthe followingmanner on the wings25 25, Figs. 1 and 2, which are iixed on the sleeve35, that Wings 25 25 are provided withA transversearms 3l, anged attheir outer ends, as shown. '0n said arms 3l are fastened the concentricrings 37 38 39 and the center plate 40. Said suction-blocks d d Pds areeach made in halves, and said halves are fastened at opposite sides ofsaid wings 25 25, respectively, between said The' bars The bars of saidinner IOO IIO4

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vis keyed to the swift-running shaft K: Said I d3 and fans G2 64 revolveinside of the innermost circle of gratings. and 5.)

The aforesaid pressure-fans EE' Ezare fastened to their respective rings37 3S 39. The outer fans E consist of main blades 45 45, which generatethe swift, strong, and sudden sifting impulse in combination with theouter deflecting-grate C, and said main fan-blades are bent forward at aconsiderable angle from the radius-to effect thepowerful outward reboundof the air-currents, which is a very important factor in generating thedesired sudden and powerful outward impulse of the sifting-current, ashereinbefore mentioned. Each ,of `the said main blades 45 is followed by-a group of auxiliary fan-blades, certain of which blades are preferablybent forward at a less angle than the main fan-blades 45. The numberof-said auxiliary blades 4S may be increased or diminished according tocircumstances, and said auxiliary blades are disposed between the mainfans 45 and the advancing side ofthe suction-blocks d. The purpose ofsaid auxiliary blades 4S is to take up the air furnished by the innerfan-blades 55 57 and the front curve 60 of the suctionblock cl3 anddeliver it in a strong outward after-current of large volume betweensaid main fan 45 and the advancing face of said suction-block d. Saidinner fan-blades 55 57 and curve 60 may each be either used singly, asshown, or be followed or even replaced by groups of fan-blades, asindicated by reference to letter N, Fig. 6. The .air delivered by saidfans 55 57 and curved surface 60 to the auxiliary fans 48, and by saidfans 48 sent through the sieve as a strong outward after-current oflarge volume, blows the material which has been sifted by the mainoutward sifting-current which `was developed by the main fans 45 so farfrom the sieve that it cannot be caught and brought back by the nextinward current. Said fan-blades 55 57 and curved surface G0 (or theircorresponding groups of fan-blades) are so shaped and disposed in themachine as to provide the largest possible area for the outflowing airand to offer the least possible resistance thereto. Therefore, as willbe observed on (Compare Figs. 1

inspection of the drawings, the passages between the fan-blades arepreferably enlarged in the direction of the air-How, and in this mannernot only does a large volume of air pass to the point of discharge ofand form the outward after-current, but said air also powerfully sweepsthe under sides of the fanblades and prevents the accumulation of lineparticles of material in the interior of the machine.

Suction-blades 62 64, auxiliary to the innermost suction-block d3, maybe xed between the center plates 40 in any desired manner, or suchauxiliary blades may be omitted and the shape of the block d3correspondingly changed without affecting materially the re,- sult.

Any suitable drivin g-gear may of course be used, and I prefer thefollowing arrangement: A shaft S0, provided in the usual manner withfast and loose driven pulleys 8l, respectively, carries a cone S4 anddriving-pulleys SG. A half-turn belt S8 from said pulley S5 drives aworm 90, which meshes with a worm-gear 01 of the sieve B, therebyimparting a slow rotation to said sieve. A belt 95 from pulley S6 drivesa pulley 98, fixed on the hub 27 of the gratings. A cone 100 is drivenfrom cone 84 through the medium of the shiftable endless belt 101, whichis equipped with any suitable belt-shipper, and a p ulley 102, fixed onthe shaft 103 of said cone 100, drives pulley 105 on the aforesaidswift-running shaft K, on which are fixed, as hereinbefore described,the pulsators, (fans and vacuum -generators.) Thus by `shifting belt 101the speed of said fans and vacuum-generators may be varied according tothe nature of the material without varying the speed of the sieve or thegratings.

The machine operates as follows: The material to be sifted having beenfed through the chute X works into the basket G, and falling from thenceis worked by the spiral blade 75 into the annular space between thedeflectinggrate and sieve. Now the long andstrong inward air-cu rrentclears the sieve of adhering particles of the material and brings alarge volume of air into the machine. A certain proportion of this airis crowded upon and rebounds powerfully outward from the main fan-blades45, developing a very strong, swift, and sudden outward current, whichsifts the finer particles of the material through the sieve. Theremaining part of the in brought air iows freely into the interior ofthe machine, as described, and to the auxiliary fans 48, between thesaid main sifting-fans 45 and the front side of suctionblocks d, and ishere expelled as a long and strong outward after-current, blowing thesifted particles far from the sieve. Then follows the next inwardcurrent, and so the cycle repeats itself continuously all around thesieve. The aforesaid inward and outward currents may be considered to bedue to the crests of high pressure and the hollows of low pressure of anair-wave of peculiar nature, which is produced by my apparatus andpropelled around the sieve, a wave which I believe to be essentiallyunlike any heretofore generated in sifting-machines.

As hereinbefore stated, the process which ICO IIO

is the subject of my present application-is not limited toany'particular form of apparatus, and the apparatus herein shown anddescribed are only used as illustrations of good forms of machines foroperating the process. Said machines are not herein claimed,but areseverally the subject of claims in other of\my applications for patentsof the United States.

and N inner blades which cooperate with the `grating J2 to deliver theair to the said auxiliary fans M. O O2 are auxiliary suctionblades xedon the heads which carry the blocks F F2. The airburrents generated bythis machine agree in their general character with those generated bythe machine illustrated in Figs. `1 to 5 and operate the same process ofsifting.

In the machine shown in Fig. 7 I employ` l only one set ofsuction-blocks F3 and one defleeting-grate J3. L is thev main fan; M',the auxiliary fans for aiding in generating the outward after-current,as hereinbefore described. P P are blades revolving in the samedirection as the deilecting-grate J 3 and either driven from the samehub or separately, as desired. I now prolong the suction-blocks F2backwardly by plates f3, as shown, whereby I increase and prolong theinward current, and in cooperation with said blades P P prevent theinjurious action of the return currents hereinbefore referred to.

The machine shown in Fig. 8 is analogous to that shown in Fig. 7 but Inow replace the blades P by the grating P, which revolves in the samedirection as deiiectin'g-grate J3 and may be driven from the same hub orseparately, as desired, and the bars of said grating P may be wider thanshown in any desired degree. Both these machines generate substantiallythe same air-wave as the machine shown in Figs. 1 to 5 and operate thesame process. l

Fig. 9 illustrates a cross-section of the preferred machine, whereinAthe arrangement of pulsators is in general similar t-o that of'Fig. 5.It differs, however, from the lastenamed machine in two respects. First,the suctionblocks d6 dl d8 019 are lengthened out, as shown, to effectthe control of the volume and distribution of the air referred to above,and, second, the center of the machine is open between the innersuction-block and the hub, with only a single grating between saidsuction-block and hub. The opening in the center was also shown in Fig.8, and the machines of Figs. 8 and 9 both demonstrate the fact that theuse of pockets or cells open only toward the periphery, but closedtoward the center, which were an essential characteristic of allmachines that have been heretofore known as wave-generators, is notessential in Vmy new machines.

Thus comparison of Figs. 5 to 9, inclusive, proves that my process is,as before stated, independent of any special machine and depends uponthe generation in any manner of suitable air-currents and the subjectingto such currents of the materials to be sifted in the mannerhereinbefore described. In each of said figures I have indicated thedirection of the air-currents and approximately their strength by arrowson'one-half the figures. The distribution of the aircurrents is the sameon the other half of the figures, but the arrows are there omitted topermit clear representation of the parts of the machines.

Now, having described my improvements, I claim as my invention- Theprocess of sifting granular materials hereinbefore described, consistingin first clearing the sieve by long and strong inward currents of air oflarge volume, then propelling a part of this air in a strong, swift andsudden blast outward through the sieve, whereby the finer particles ofthe material are sifted through the sieve, and following this blast witha long and strong outward Lafter-current'of the remainder of the airwhereby the sifted particles 'are blown far from the sieve and out ofreach of the next inward curf rent, and causing said several currents totravel successively over all parts of the sieve.

In testimony that I claim the foregoing as my invention I have signed myname, in presence of two witnesses, this 12th day of August, 1896.

FRIEDRICH GEORG WINKLER.

Witnesses: A BERNARD J. IsEcxE, HENRY V. BRowN.

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